Circuit controlling mechanism



Patented Oct. 27, 1931 UNITED STATES PATENT OFFICE manna I. SGEWKE'NIEE, 0] S CKEITBCTADY, NEW YORK, ABBIGNOR '10 onmau.

COMPANY, A COREORLTION OF NEW YORK CIRCUIT CONTROLLING Application fled November 1, 1829. Serial ll'o. 404,148.

tacts in or er t at the arc shall not be drawn to excessive length before it is extinguished and in order that the circuit shall be cleared within a c cle or fraction thereof. The performance owever, of such hi h speed opening mechanism is not necessari y uniform due to the fact that the time of separation of the contacts may occur at different parts of the alternating current cycle, the interru tion 0 of the arc being more easily accomplished when the current is at or near its zero value in the cycle, and more diflicult when it is at or near its maximum value.

It is a princi al object of my invention to provide ccntro 'ng means for causing openmg movement of switch contact structure, articularly of the high speed type, at or uring the period when the current traversin the contact structure is at a minimum. 8 it is a further object of my invention to provide controlling means for high speed switch operating mechanism which shall release a holding or latching member when the switch is to be opened during the period in which the current traversing the switch is at or near a maximum value, and which shall subsequently actuate a tripping member to cause opening movement of t e switch during the subsequent period when the current is at or near a minimum value.

My invention will be-more fully set forth in the followin description referring to the accompanying rawings, and the features of novelty which characterize my invention will 45 be pointed out with particularity in the claims annexed to and forming a part of this specification.

Referring to the drawin Fig. 1 is an elevational view in section ilustrating circuit controlling mechanism embodying my in-.

vention; Fig. 2 is a fra enta view of a paratus illustrated in 1 in inother pos ition, and Fig. 3 is a grap 'c illustration of a cycle of alternating current.

In Fig. 1 there is illustrated by way of example big? spleed circuit interruptin apparatus of t e c aracter describedand c aimed in my Patent No. 1,721,417 of July 16, 1929.

The circuit interrupting apparatus comprises 1 a tank 1 and a superstructure 1 within which are dis osed the coactin the switch structure. e contact structure ma be immersed in an insulating fluid 4, suc as oil, the contact 3 being stationary and the contact 2 pivotally mounted at 5 for movement relative thereto. In the closed circuit position illustrated, the movable contact 2 is maintained in engagementwith its coacting stationary contact 3 by means of a closmg spring 6 attached at one end to a fixed point 6' and at its other end to a floatin lever 8, as at 9. A dash pot device 7 is li ewise connected between the points 9 and 6. The lever 8 is centrally pivoted at 8 and at its opposite end is connected at 10 to the contact operating rod 11. The pivot 8 in the position illustrated is held stations by controlling means presently descri so that the tension of the closing spring 6 is effective to bias the flpating lever 8 and consequently the movable contact 2 in a counter-clockwise direction to maintain the switch contacts closed.

The switch opening spring 12 is secured at one end to a fixed support 18 and at its opposite end to the pivot 8', the spring 12 being under tension in the closed clrcuit position. It will therefore be apparent that'when the forces restraining the pivot 8' in its stationary position are removed, the comparatively strong opening spring 12 will immediately cause clockwise rotation of the floating lever 8 about its end pivot 9 to effect openin movement at high speed of the contact 2. bulfer or shock absorber 12 is provided and arranged to be engaged by the lever 8 asit reaches the open circuit osition.

When the swimh is to reclosed, the pivot 8' must be again restrained in its original stationary position, otherwise downward or contacts 2 and 3 of sion. The spring 6, however, is sufiiciently strong to thereupon rock the lever 8 in a counter-clockwise direction about the now stationary pivot 8 to close the switch.

The switch operating mechanism so far described is illustrated in complete detail in my aforesaid Letters Patent, and the foregoing description is believed to be sufiicient .in order that the controlling mechanism therefor embodying my invention may be clearly understood.

For the purpose of maintaining the floating ivot 8 stationary under conditions in whic. the switch is to be closed, and to permit it to float when the switch is to be opened, there is provided electro-magnetical- 1y controlled means responsive to the magnitude of the current traversing the switch. To this end, the ivot 8 is connected through a link 16 to a be ll crank 17 which is pivoted to the superstructure 1 at 18. The other end of the bell crank is provided with a camenga 'ng face 19. It will be accordingl note that clockwise movement of the be crank 17 from the osition illustrated causes the pivot 8' to be owered and to assume a floating position so that the spring 12 may immediately open the switch.

For the purpose of restraining the bell crank 17 so that it serves under predetermined conditions to maintain the pivot 8' stationary, there is provided a holding member comprising a lever 20 ivoted at 21 and abutting at its free end t e face 19 of the bell crank. As long as the holdin 20 is in the position illustrated the member ll crank .17 is restrained from clockwise movement and the ivot 8 is maintained stationary. The hol lever 20 may be lifted out of engagement with the bell crank face 19 by an electro-magnet 22 coacting with an arm ture 23 secured to the holding member. An adjustable spring 24 serves to prevent attraction of the armature 23 and consequent clockwise rotation of the holding member 20 to free the bell crank until the electro-ma et 22 has been energized to a predetermine extent.

The electro-magnet 22 may beenergized through a current transformer 25 connected in the line which is controlled by the switch structure 2-3. Likewise controlled by the electro-magnet is a tripping member 26 pivoted at 21 and havin a camming ed e 27 at its outer or free end. e tripping ever 26 is also provided with an armature 28 for coactwith the electro-inagnet. In order that the invention may be more clearly illustrated,

the camming edge 27 as illustrated in Fig. l, is spaced at an exaggerated distance from the end of the bell crank.

Referring now to Fig. 3, and assuming that the electro-magnet 22 is energized by an overload or short circuit of sufiicient magnitude to attract the armature 23, it will be apparent that the actuation of the armature will occur at some part of the cycle, as at 30, where the current has rapidly risen to near its maximum value. Accordingly, the holding lever 20 is moves. pwardl out of the path of the upper end of the bel crank, thereby permitting the same to move slightly in a clockwise direction to engage the cammin face 27 of the tripping lever 26, as illustrate in Fig. 2. As the electro-magnet 22 is still strongly energized, the armature 28 on the tripping lever 26 is maintained in position and will restrain the bell crank 17 from further movement. As the current passes its maximum and approaches its subsequent minimum value 0 the cycle, the current will reach a value as at 31, at which value the electromagnet 22 is no longer energized sufliciently to maintain the trippin lever 26 in a position restraining the befi crank lever. Accordingly, the sprin 12 actin through the bell cran causes the ree end 0 the bell crank engaging the cam face 27 to cam or move the tripping member upwardly and out of restraining en agement with the bell crank. The bell cra ted to rotate in a clockwise direction under the influence of the s ring 12 to cause rapid opening movement 0 the switch at, or near, the minimium value of the current traversing the same.

Resettin of the tripping mechanism is automatica 1y accomplished during the closing operation of the switch mechanism during which the bell crank 17 is rotated counter-clockwise to the position illustrated in Fig. 1 so that the holding member 20 may slide into enga ment with the face 19 under the influence o s ring 24. The tripping lever 26 may be biase by gravity or other suitable means to a position where the cam face 27 is normally in the path of the bell crank.

It shall be understood that my invention is not limited to the specific type of switch closing mechanism associated therewith, and that modifications and changes in the specific structure and arrangement thereof will occur to those skilled in the art, without departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In circuit interrupting apparatus comprising relatively movable contact structure, the combination of 0. rating means, means normally biasing said operating means towards an open circuit position, and means for restraining said operating means in a closed circuit position, said restraining means beis thereupon instantly permiting responsive to predetermined overload conlast named means being responsive to ourrent conditions whereby the switch operating means are permitted to move under the influence of said biasing means to open circuit position during a minimum value of the current traversing the contact structure.

3. In circuit interrupting apparatus, comprising relatively movable contact structure, the combination of operating means for said structure, means biasing said operating means towards open circuit position, electro-mag netic means responsive to the current traversing the contact structure, means controlled by said electro-magnetic means for initially releasing the operating means in response to a predetermined excess of current, and means for subsequently releasing the operating means to cause opening movement of the contact structure during the subsequent part of a cycle in which the current is at a minimum.

4. In circuit interrupting apparatus comprising relatively movable contact structure, means normally biasing said contact structure towards open circuit position, means for restraining said contact structure in closed circuit position, and electro-magnetically controlled means for moving in'response to excess current a restraining member normally maintaining the switch structure closed, and for subsequently restraining the said structure in closed circuit position until the current has substantially reached its minimum part of the cycle.

5. Circuit interru ting apparatus comprising in combination relatively movable contact structure, means biasing said structure towards open circuit position, holding means for restrainin the contact structure in closed circuit position during normal current values, said holding means being actuated to release the contact structure in response to a predetermined excess of current, and latching means for further restraining the switch contact structure in closed position until the current has decreased to near its minimum value in the cycle.

6. Circuit interrupting ap aratus comprising in combination relatively movable contact structure, means biasing said'structure towards open circuit position, a member for restraining the contact structure in closed circuit position, and electro-magnetically controlled means coacting with said restraining member comprising a holding member for preventing opening movement of the switch during normal current values, said holding member being. moved out of engagement with the restraimng member in response to predetermined excess of current, and tripping means for subsequently preventing opening movement of the contact structure until the current has decreased to near its minimum fieriod in the cycle.

7. n circuit interrupting apparatus comprisin relatively movable contacts, means contro ling the opening movement of said contacts comprising a member normally holdin the contacts in closed circuit POSI- tion, e ectro-ma etically controlled means for releasing thfi'i olding member in response to a predetermined excess of currenttraversing the contacts, and means controlled by the electro-magnetic means for maintaining the contacts in closed position until the ourrent has decreased to near its minimum value.

movable contacts and means for biasing the movable contacts towards its open circuit sition, of means for controlling the openmg movement of the movable contact comprising a holding member for restraining the movab e contact in its closed position during normal current, electro-magnetic means for moving the holding member out of its restraining position in response to excessive current traversing the contacts, said holding member being actuated during the period in which the current is a maximum, and a second member for restraining the movable contact in its closed position independently of the aforesaid holdin member by said electromagnetic means, said second member being released to permit opening of the movable contact when the current has decreased to the subsequent minimum period of the cycle.

9. The combination with circuit interrupting apparatus comprising stationary and movable contacts and means for biasin the movable contact to its open circuit position, of means for controlling the opening movement of the movable contact comprising a rotatable member, and operative connection between said rotatable member and the movable contact whereby the rotatable member may be restrained so as to maintain the movable contact in closed position", a lever for normally en aging and restraining said ro tatable mem r, an electro-magnet responsive to the current traversin the contacts for moving said lever out of its restraining engagement upon occurrence of excessive tho means for biasing the movable contact towards open position overcomes the to straining influence of the second lever during the period in which the current is a. minimum.

In witness whereof, I have hereunto set 5 my hand this 31st day of Gctober, 1%29.

CHARLES F. SCHWENNKER. 

